It is possible that the main title of the report Marfan Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
As Jenny points out, being able to lisp the alphabet song at age two has little to do with 'knowing' the alphabet. And, yes, most children learn the letters by sight and sound in kindergarten, although most are capable of learning this information sooner if diligently taught by parents or others.
How babies learn language: Unraveling the mystery. From birth to age 7, children are geniuses at learning language. After that, the ability starts dropping dramatically before leveling out at 17 or 18. How babies learn language â what goes on in their brains â is a mystery still being unraveled.